Electric lamp base end structure



R. J. AYRES Nov. 10, 1964 ELECTRIC LAMP BASE END STRUCTURE Filed Dec. 28, 1960 lnven tov'. Reginald J. Agres EL/5 2 is A t orneg United States Patent 3,156,841 ELEQTREQ LAMP BASE END ETRUCTURE Reginald .i. Ayres, Shaker Heights, @hio, assignor to General Electric Company, a corporation of New York Filed Rec. 23, 196i Ser. No. 79,830 3 illlainis. Cl. 313-49) This invention relates to electrical devices such as incandescent lamps and gaseous discharge devices, and more particularly to a base end construction for such devices.

Double-ended miniature incandescent lamps of the type having terminal contact means or a base structure at each end are in general use at present for Various applications, such as automotive dome and dash lighting and tail lamps. Such double-ended lamps are adapted for use with simple spring clip type sockets similar to those commonly used for cartridge fuses, for example.

In the most common form of miniature double-ended incandescent lamp in general use at present, the tubular lamp envelope is provided at its opposite ends with base structures in the form of cylindrical metal shells which serve as the terminal contacts for the lamp. In the use of the lamp, these cylindrical metal base ends are snapfitted between the respective pairs of spring-clip fingers of the lamp socket to thereby mount the lamp in place in the socket and form the electrical connection between the lamp terminal contacts and the socket contacts.

Another form of miniature double-ended incandescent lamp that has been proposed for the same service applications is of the so-called baseless type disclosed and claimed in copending application Serial No. 848,282 Ayres et al., filed October 23, 1959 and assigned to the assignee of the present invention. The baseless lamp therein disclosed comprises an elongated glass bulb or envelope provided at its opposite ends with protruding fiat glass stem press portions through which the lead-in wires of the lamp are sealed. The lead-in Wires are bent around the ends of the lamp stem press portions to extend back therealong and lie flat against one of the fiat side faces of the respective stem press within a generally U or V shaped longitudinal groove therein, the portions of the lead-in wires within the grooves serving as the terminal contacts for the lamp.

While such baseless type double-ended lamps are adapted to be used in spring-clip type sockets similar to those used for the conventional type double-ended lamps provided with cylindrical base ends, they are not useable, without further structural changes, in the spring-clip type sockets which are normally employed for such conventional cylindrical base type double ended lamps. This is so because of the fact that the flat protruding glass stem press portions of the baseless type lamps are of insuificient thickness to fit tightly between and engage the spring-cl p fingers of the conventional type socket end, in addition, they are not formed with terminal contacts which would engage with the spring contact fingers of the socket to electrically connect the lamp thereto. As a result, such baseless type double-ended lamps are not suited for interchangeable service with the conventional type of double-ended lamp.

It is an object of my invention, therefore, to provide a simple and inexpensive base end structure for electric lamps or similar devices of the type having protruding stem press portions.

Another object of my invention is to provide a doubleended electric lamp or similar device of the type having protruding fiat glass stem press portions at its opposite ends and having base structures mounted thereon and adapting the lamp for interchangeable use with present "ice conventional type double-ended lamps, in existing springclip type sockets therefor.

Still another object of my invention is to provide an adapter base for an electric lamp or similar device of the type having a protruding flat glass stem press portion, which adapter base can be quickly and easily secured in place on the stem press portion of the lamp to thereby form an effectively operating cylindrical base end structure thereon.

Briefly stated, in accordance with one aspect of the invention, an adapter base for an electric lamp or similar device of the baseless type such as referred to hereinabove, is constituted by a spring metal band of open ring shape having its ends inturned to extend approximately diametrically thereof and form resilient spring finger portions which are disposed parallel to one another in opposed spaced relation. The spring finger portions of the adapter base receive and resiliently clamp therebetween the stem press portion of the lamp, and they are formed with a cooperating pair of protuberances on their facing contact surfaces which snap loclt into the grooves in the fiat sides of the stem press to hold the adapter base securely in place on the stem press against sidewise removal therefrom and also to engage with the lead-in wire within the stem press groove to thereby form. an electrical connection therewith.

Further objects and advantages of my invention will appear from the following detailed description of a species thereof and from the accompanying drawing.

In the drawing, FIG. 1 is an elevation, partly broken away, of an electric incandescent lamp comprising my invention.

FIG. 2 is a longitudinal section of the lamp compristhe invention on the line 22 of FIG. 1, with one end of the lamp shown in elevation.

FIG. 3 is a transverse section through the lamp on the line 3-3 of FIG. 1.

FIG. 4 is a perspective view showing a lamp according to my invention inserted in place in a socket, and

FIG. 5 is a perspective view of the adapter base according to the invention.

Referring to the drawing, the invention is there illustrated as applied to an electric incandescent lamp of the double-ended type such as disclosed in the aforementioned copending Ayres et al. application Serial No. 848,282 and comprising a sealed elongated glass bulb or envelope 1 preferably of tubular shape and provided at its opposite ends wtih reduced diameter neck portions 2 terminating in protruding flat stem press portions 3 of solid glass through which lead-in wires or conductors 4 are sealed so as to protrude endwise therefrom. Interiorly of the bulb 1 the lead-in wires 4 are connected to the opposite ends of an electrical energy translation element or filament 5 of a suitable refractory metal and preferably in the form of a straight length of coiled tungsten wire supported by the lead-in wires 4 in a position extending more or less axially of the tubular envelope 1. The envelope 1 contains a suitable inert gas filling such as argon, for example, at a pressure below atmospheric.

As shown in FIG. 2, the protruding fiat stem press portions 3 at the opposite ends of the envelope 1 are disposed in the same axial plane of the lamp envelope and are formed with shallow grooves or channelways 6 of generally U or V shape on one or both of their flat side faces 7. The grooves 6 extend generally longitudinally of the envelope 1 from the outer ends 8 of the stem press portions, and they are located more or less centrally of the stem press portions 3 between their side edges. The lead-in wires 4 project outwardly from the outer ends 3 of the stem press portions 4 at points likewise located more or less centrally of the stem press portions, and they are bent back around the said ends 3 of the stem press portions to lie fiat against one or the other of the sides 7 thereof within the respective groove 6 therein so as to be concealed beneath the flat surface 7 of that side of the stem press along which the lead-in wire extends. The portions 9 of the lead-in wires 4 thus bent around the stern press portions and lying within the grooves 6 serve as terminal contacts for the lamp, and because of their concealment within the grooves 6 so as to lie below the flat surfaces '7 of the stern press portions 4, they are thereby protected against distortion such as might otherwise result from their becoming caught on objects and bent out of shape during the handling of the lamp or its insertion and removal from the lamp socket. To permit the concealment of the exposed terminal contact portions 9 of the lead-in wires 4 below the fiat surfaces 7 of the stem press portions 3, the grooves 6 in the said stem press portions are made of a depth slightly greater than the diameter of the said terminal contact wire portions 9.

The baseless lamp as thus described is adapted for use with spring-clip type sockets similar to that customarily employed for cartridge type fuses and the spring-fingers of which are specially formed to receive and resiliently clamp therebetween the flat stem press portions 3 and also fit within the grooves 6 and engage the lead-in wire portions 9 therein so as to make electrical connection therewith. However, such a baseless type lamp is not adapted to fit in the existing spring clip type sockets which are normally employed for the conventional type doubleended lamps in general use at present and having cylindrical base ends which fit between the spring-fingers of the socket. Thus, the baseless lamp is not interchangeable in use with the conventional type double-ended lamps.

In accordance with the invention, therefore, the opposite ends of such a baseless type of double-ended lamp are each provided with an open ring-shaped adapter base structure it such as shown in FIG. 5, in order to thereby afford effectively operative cylindrical base end structures on the lamp corresponding more or less to the cylindrical base shells of the conventional type double-ended lamps in general use at present. As a result, the lamp according to the invention is adapted for mounting in the existing spring-clip type sockets in general use at present for mounting of the conventional type double-ended lamps having cylindrical base shells at their opposite ends. Thus, the lamp according to the invention is completely interchangeable in use with the conventional type doubleended lamps having cylindrical base shells, for use in the. present spring-clip type sockets therefor.

The adapter base it? consists of a band of suitable spring metal, such as that commonly known as clockspring, formed into open ring or horseshoe shape, as shown at 11, with its ends inturned to extend approximately diametrically thereof and form a pair of cooperating spring finger portions 12. disposed parallel to one another in opposed spaced relation. The said pair of spring fingers 12 are spaced apart a distance slightly less than the thickness of the stern press portion 3 of the lamp so as to receive and resiliently clamp the stem press portion tightly therebetween when it is forcibly inserted sidewise into the space in; (PEG. between the spring fingers.

To hold or lock the adapter base iii securely in place on the stem press 3 against unintentional sidewise re- .moval therefrom and, in addition, make electrical connection'with the lead-in wires of the inserted lamp, one or both of the cooperating pair of spring fingers 12 are provided with protuberances id, preferably in the form of U or V shaped ridges or ribs on the facing contact surfaces of the spring fingers and extending parallel to the axis of the ring-shaped portion of the adapter base, which protuberances l4 correspond to and match the grooves 6 in the stem press portions 3 so as to snugly fit and snaprlo ck into the said grooves and contact the e, 1 see-i1 lead-in wire portions lying therewithin to form an electrical connection therewith. The assembly of the adapter base 10 onto the stem press 3 is accomplished.

simply by forcibly inserting the stem press sidewise into the space 13 between the spring fingers 12 to wedge them apart, and continuing the insertion movement until the protuberances or ridges 14 on the spring fingers snap into the grooves 6 in the stem press.

The forming or shaping of the spring metal band or clock-spring material to the final shape of the adapter base 1b is preferably performed while the spring band material is in an annealed or so-called softened state characterized by the absence of any springiness so that it is capable of being easily shaped or formed to the configuration of the adapter base. The final shaped adapter base it is then subjected to the conventional spring tempering process in which it is heated to an elevated temperature, e.g., of the order of 1460" F. or so, and then suddenly quenched in oil or other suitable quenching medium, after which it is re-heated to draw it to the proper temperature at which it acquires its spring characteristics. To assure a good electrical contact of the adapter base it) with the lead-in wire portions 9 of the lamp and with the lamp socket contacts, the adapter base it is desirably plated with silver or nickel or other good electrically conductive material.

By providing each end of the lamp with. an adapter base it in accordance with the invention, the resulting lamp is therefore formed with base end structures of effectively operating cylindrical shape such as adapt the lamp for interchangeable use with previous conventional type double-ended lamps having cylindrical metal base' velop provided with a protruding fiat stem press portion of solid glass having a channelway in at least one of its flat sides extending therealong from its outer end, a lead-in conductor sealed into said stem press portion and protruding endwise therefrom, said conductor being bent around the outer end of said stem press portion and lying flat against one of the said flat sides thereof within the said channelway therein so as to lie below the surface of the said one flat side and form a terminal contact for the device, and a base mounted on said stem press portion and comprising a spring metal band of open ring shape circumposed about said stem press portion and having its ends inturned to extend approximately diametrically of the ring-shaped base and form resilient spring finger portions disposed parallel to one another in opposed spaced 'relation and between which the said flat stem press portion is received and resiliently clamped tightly in flatwise postion therebetween, one of said finger portions having a protuberance on its contact face snap-locked within the said channelway in said stern press portion to hold the base securely in place thereon against sidewise removal therefrom and firmly engage with the said conductor in said channelway to form a good electrical connection therewith.

2. An electrical device comprising a sealed glass envelope provided-with a protruding flat stem press portion of portion to lie flat against one of the flat sides thereof within the said groove therein so as to lie below the surface of the said one flat side and form a terminal contact for the device, and a base mounted on said stem press portion and comprising a spring metal band of open ring shape eircurnposed about said stem press portion and having its ends inturned to extend approximately diametrically of the ring shaped base and to form resilient spring finger portions disposed parallel to one another in opposed spaced relation and between which the said fiat stem press portion is received and resiliently clamped tightly in fiatwise position therebetween, the said finger portions having ridge-like protuberances on their oppose contact faces snap locked within the said grooves in the respective fiat sides of said stem press portion to hold the base securely in place thereon against sidewise removal therefrom and to firmly engage one of said finger portions with the said lead-in wire in the respective groove to thereby form a good electrical connection therewith.

3. An electric lamp comprising a sealed tubular glass enevelope provided at its opposite ends with protruding flat stein press portions of solid glass disposed in a common plane, each of said flat stem press portions having parallel shallow U shaped grooves in its opposite flat sides extending longitudinally of said envelope and disposed opposite one another, lead-in wires sealed through respective ones of said stem press portions and extending into said envelope, a filament disposed within said envelope and connected at its opposite ends to said lead-in wires, said lead-in Wires protruding endwise from said stem press portions and being bent around the ends thereof to lie flat against one of the flat sides of the stern press within the said grooves therein so as to lie below the surface of the respective fiat side and form terminal contacts for the lamp, and an adapter base mounted on each of said stern press portions and comprising a spring metal band of open rin shape circumposed about the respective stem press portion and havng its ends inturned to extend approximately diametrically of the ring-shaped base and form resilient spring finger portions disposed parallel to one another in opposed spaced relation and between which the said fiat stem press portion is received and resiliently clamped tightly in fiatwise postion therebetween, each of said finger portions having ridge-like proturberances on their opposed contact faces snap locked within the said grooves in the respective stem press portion to hold the base securely in place thereon against sidewise removal therefrom and to firmly engage one of said finger portions with the lead-in wire in the respective groove to thereby form a good electrical connection therewith.

References Cited in the file of this patent UNITED STATES PATENTS 693,222 Boehrn Feb. 11, 1902 1,836,024 Harase Dec. 15, 1931 1,965,843 Foulke Apr. 25, 1933 2,705,310 Hodge Mar. 29, 1955 2,889,533 Nielsen June 2, 1959 FOREIGN PATENTS 572,618 Great Britain Sept. 17, 1945 889,970 France Ian. 25, 1944 

1. AN ELECTRICAL DEVICE COMPRISING A SEALED GLASS ENVELOP PROVIDED WITH A PROTRUDING FLAT STEM PRESS PORTION OF SOLID GLASS HAVING A CHANNELWAY IN AT LEAST ONE OF ITS FLAT SIDES EXTENDING THEREALONG FROM ITS OUTER END, A LEAD-IN CONDUCTOR SEALED INTO SAID STEM PRESS PORTION AND PROTUDING ENDWISE THEREFROM, SAID CONDUCTOR BEING BENT AROUND THE OUTER END OF SAID STEM PRESS PORTION AND LYING FLAT AGAINST ONE OF THE SAID FLAT SIDES THEREOF WITHIN THE SAID CHANNELWAY THEREIN SO AS TO LIE BELOW THE SURFACE OF THE SAID ONE FLAT SIDE AND FORM A TERMINAL CONTACT FOR THE DEVICE, AND A BASE MOUNTED ON SAID STEM PRESS PORTION AND COMPRISING A SPRING METAL BAND OF OPEN RING SHAPE CIRCUMPOSED ABOUT SAID STEM PRESS PORTION AND HAVING ITS ENDS INTURNED TO EXTEND APPROXIMATELY DIAMETRICALLY OF THE RING-SHAPED BASE AND FORM RESILIENT SPRING FINGER PORTIONS DISPOSED PARALLEL TO ONE ANOTHER IN OPPOSED SPACED RELATION AND BETWEEN WHICH THE SAID FLAT STEM PRESS PORTION IS RECEIVED AND RESILIENTLY CLAMPED TIGHTLY IN FLATWISE POSTION THEREBETWEEN, ONE OF SAID FINGER PORTIONS HAVING A PROTUBERANCE ON ITS CONTACT FACE SNAP-LOCKED WITHIN THE SAID CHANNELWAY IN SAID STEM PRESS PORTION TO HOLD THE BASE SECURELY IN PLACE THEREON AGAINST SIDEWISE REMOVAL THEREFROM AND FIRMLY ENGAGE WITH THE SAID CONDUCTOR IN SAID CHANNELWAY TO FORM A GOOD ELECTRICAL CONNECTION THEREWITH. 